CN114284014A - High-temperature non-aging iron powder core and preparation method thereof - Google Patents
High-temperature non-aging iron powder core and preparation method thereof Download PDFInfo
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Abstract
The invention provides a high-temperature non-aging iron powder core and a preparation method thereof, relating to the technical field of electronic elements. The invention adopts reduced iron powder as a main raw material, carries out acidification modification pretreatment on the reduced iron powder, then uniformly mixes the reduced iron powder with a high-temperature insulating agent and a high-temperature binder, then presses the mixture into an iron powder core, and coats epoxy resin paint on the prepared iron powder core to obtain the high-temperature non-aging iron powder core, thereby endowing the invention with the characteristics of high resistance, stable magnetic conductivity and low loss, and being capable of durably and stably operating at high temperature. The preparation process of the invention has no pollution of organic solvent, low cost and environmental protection.
Description
Technical Field
The invention relates to the technical field of electronic elements, in particular to a high-temperature non-aging iron powder core and a preparation method thereof.
Background
The iron powder core is a common magnetic material in the field of electronic elements, and is widely used due to low price, excellent direct current superposition performance and high electromagnetic performance. In recent years, in order to comply with the low-carbon economic development trend, the permanent magnet motor is gradually developed towards high efficiency, miniaturization and high frequency. In the field of traditional high-frequency motors, iron, silicon and nickel alloy materials are generally adopted to manufacture the motors so as to obtain the high-frequency motor with high frequency, high magnetic conductivity and low loss, but because eddy current loss is difficult to be effectively controlled, heat loss is high, and the performance of the motor is difficult to meet the high-frequency requirement. The iron powder core is widely used for manufacturing miniaturized and high-frequency energy-saving environment-friendly motors due to the characteristics of high magnetic conductivity, high resistivity and low loss.
In the prior art, the iron powder core belongs to a ferromagnetic material, has high magnetic flux and high magnetic conductivity, but has the defects of low resistivity and large magnetic loss, and is difficult to meet the manufacturing requirements of high resistivity, high magnetic conductivity, miniaturization and low loss of a permanent magnet motor. Core losses are mainly core eddy current losses and hysteresis losses. The traditional iron powder core is below 200 ℃, the stress is not thoroughly eliminated, the hysteresis loss is high, and the defects of low resistance, high eddy current loss, large magnetic loss and the like caused by insufficient insulation of a magnetic core lead to the great reduction of the service life of a device, so that the working requirement of the existing motor is difficult to meet. Chinese patent CN1167990A discloses an iron powder core, iron powder for the iron powder core and a preparation method of the iron powder core, wherein the method adopts an organic-inorganic composite insulation mode to obtain a high-temperature-resistant insulation coating film, and the iron powder core is prepared by curing treatment at 50-250 ℃, powder briquetting and annealing at 550-650 ℃ in an inert atmosphere, and although the operation can be carried out at higher temperature, the defects of poor fluidity, large high-frequency loss, short service life and the like exist. Therefore, in order to ensure excellent operation performance of the motor, it is necessary to develop a low-loss, high-resistivity, high-magnetic performance, and long-life iron powder core for high-temperature operation.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a high-temperature non-aging iron powder core and a preparation method thereof.
In order to achieve the above object, the present invention provides the following technical solutions:
on one hand, the invention provides a high-temperature non-aging iron powder core which is mainly prepared from the following raw materials:
100-500 parts of reduced iron powder, 10-100 parts of mixed acid solution, 1-10 parts of inorganic high-temperature insulating agent, 10-200 parts of inorganic high-temperature binder, 10-100 parts of organosilane coupling agent, 10-50 parts of lubricant, 1-20 parts of epoxy resin paint and 10-200 parts of water.
Further, the purity of the reduced iron powder is 95% or more, specifically 98% or more, and preferably 99% or more.
Further, the particle size of the reduced iron powder is 50-500 meshes, specifically, the particle size of the reduced iron powder is 100-400 meshes, and preferentially, the particle size of the reduced iron powder is 100-300 meshes.
Further, the mixed acid solution is composed of 0.5-5% by mass of phosphoric acid, 0.01-1% by mass of an oxidizing agent, and 0.001-0.05% by mass of an organic acid, specifically, 0.5-3% by mass of phosphoric acid, 0.01-0.5% by mass of an oxidizing agent, and 0.001-0.03% by mass of oxalic acid, and preferably, 0.5-2% by mass of phosphoric acid, 0.01-0.1% by mass of an oxidizing agent, and 0.001-0.02% by mass of oxalic acid.
Still further, the oxidizing agent is a combination of at least one of nitric acid, chromic acid, hydrogen peroxide, potassium permanganate, sodium hypochlorite and ozone, specifically, the oxidizing agent is a combination of at least one of nitric acid, chromic acid, hydrogen peroxide and potassium permanganate, preferably, the oxidizing agent is a combination of at least one of nitric acid, chromic acid and hydrogen peroxide.
Further, the organic acid includes a combination of at least one of oxalic acid, citric acid, malic acid, acetic acid, ascorbic acid and butyric acid, specifically, the organic acid includes a combination of at least one of oxalic acid, citric acid, malic acid and acetic acid, preferably, the organic acid includes a combination of at least one of oxalic acid, citric acid and malic acid.
Further, the phosphoric acid is 0.1 to 3.0% by weight of the fine reduced iron, specifically, 0.1 to 1.0% by weight of the fine reduced iron, and preferably, 0.1 to 0.8% by weight of the fine reduced iron.
Further, the organic acid is 0.001 to 0.05% by weight of the fine reduced iron, specifically, further, 0.001 to 0.03% by weight of the fine reduced iron, and preferably, 0.001 to 0.01% by weight of the fine reduced iron.
Further, the inorganic high-temperature insulating agent is a combination of at least one of yttrium oxide, zirconium oxide, holmium oxide, cerium oxide, tantalum oxide, titanium oxide, silicon oxide, aluminum oxide, and the like, specifically, the inorganic high-temperature insulating agent is a combination of at least one of yttrium oxide, zirconium oxide, cerium oxide, holmium oxide, tantalum oxide, and the like, and preferably, the inorganic high-temperature insulating agent is a combination of at least one of yttrium oxide, zirconium oxide, cerium oxide, and the like.
Further, the inorganic high-temperature binder is composed of at least one of alumina, silica, boria, magnesia, zirconia, zinc oxide, and calcium aluminate, specifically, the inorganic high-temperature binder is composed of at least one of alumina, silica, boria, zinc oxide, and zirconia, and preferably, the inorganic high-temperature binder is composed of at least one of alumina, silica, and zirconia.
Further, the lubricant comprises at least one of zinc stearate, graphite powder, mica, talcum powder, barium hydroxide and borax, specifically, the lubricant comprises at least one of zinc stearate, graphite powder, mica and borax, preferentially, the lubricant comprises at least one of zinc stearate, graphite powder and mica.
On the other hand, the invention provides a preparation method of a high-temperature non-aging iron powder core, which comprises the following steps:
1) weighing reduced iron powder according to the weight part ratio, pouring a certain weight part of water, and stirring and wetting;
2) adding a mixed acid solution into the material obtained after wetting in the step 1), uniformly stirring, heating to react for a period of time, and stir-frying the iron powder to be dry;
3) adding water into the mixture obtained in the step 2), stirring the mixture to be fully wetted, adding an inorganic high-temperature insulating agent, stirring the mixture until the mixture is uniformly mixed, adding an inorganic high-temperature binder, stirring the mixture uniformly, adding an organosilane coupling agent, continuously stir-frying the mixture until the mixture is dry, adding a lubricant, and continuously stirring the mixture until the mixture is uniformly mixed to obtain a mixture;
4) pressing the mixture obtained in the step 3) into a dust core;
5) annealing and heat-treating the iron powder core prepared in the step 4), cooling to room temperature, and then performing vibration grinding to remove burrs;
6) and 5) spraying epoxy resin paint on the iron powder core prepared in the step 5), and airing to obtain the high-temperature non-aging iron powder core.
Further, the amount of water used in step 1) is 1/10-1/3 of the fine reduced iron, specifically 1/10-1/5 of the fine reduced iron in step 1), and preferably 1/10-1/8 of the fine reduced iron in step 1).
Further, the temperature after temperature rise in the step 2) is 80-200 ℃, specifically, the temperature after temperature rise in the step 2) is 80-190 ℃, and preferentially, the temperature after temperature rise in the step 2) is 100-180 ℃.
Further, the reaction time of step 2) is 1 to 10 hours, specifically, the reaction time of step 2) is 2 to 8 hours, preferably, the reaction time of step 2) is 4 to 6 hours.
Further, the concentration of the inorganic high-temperature binder in the step 3) is 0.5 to 5.0%, specifically, the concentration of the inorganic high-temperature binder in the step 3) is 0.5 to 3.0%, and preferably, the concentration of the inorganic high-temperature binder in the step 3) is 0.5 to 2.0%.
Further, the pressing pressure in the step 4) is 5-20T/cm3Specifically, the pressing pressure in the step 4) is 7-15T/cm3Preferably, the pressing pressure in step 4) is 8-12T/cm3。
Further, the annealing temperature in the step 5) is 100-.
Further, the annealing heat treatment time in step 5) is 1 to 8 hours, specifically, the annealing heat treatment time in step 5) is 1 to 5 hours, and preferably, the annealing heat treatment time in step 5) is 2 to 4 hours.
Further, the duration of the vibromilling in step 5) is 10 to 120 minutes, specifically, the duration of the vibromilling in step 5) is 20 to 90 minutes, and preferably, the duration of the vibromilling in step 5) is 30 to 60 minutes.
Further, the thickness of the epoxy resin paint film in the step 6) is 0.1-0.5mm, specifically, the thickness of the epoxy resin paint film in the step 6) is 0.1-0.5mm, and preferentially, the thickness of the epoxy resin paint film in the step 6) is 0.1-0.3mm.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the invention, the surface layer of the reduced iron powder is formed with a layer of uniform insulating film by performing passivation pretreatment on the reduced iron powder in the mixed acid solution, so that the resistance of the iron powder core is improved, and the accelerated aging caused by temperature rise in the working process is reduced;
2. by adding an inorganic high-temperature insulating agent and an inorganic high-temperature binder, a layer of high-temperature insulating layer wraps the reduced iron powder particles to form a large amount of insulating iron powder particles, so that the high-resistivity, high-magnetic flux density, low loss and excellent high-temperature resistance are further endowed with the invention, the eddy current loss is prevented from being generated, and the aging caused by high temperature is prevented;
3. the inorganic high-temperature insulating agent and the inorganic high-temperature binder used in the invention can firmly bond the iron powder at high temperature, and further ensure that the magnetism of the iron powder core is not greatly reduced when the iron powder core works at high temperature, thereby ensuring that the invention keeps stable, durable, higher permanent magnetic performance and longer service life;
4. the resistivity of the invention is 65 mu omega m, and the magnetic flux density (10 kA/m) is 1.8T, core loss (f =50Hz, Bm =1.0T) lower than 40 mw/cm3；
5. The preparation method uses water as a solvent, has low cost, does not produce organic pollution and is environment-friendly.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
A preparation method of a high-temperature non-aging iron powder core comprises the following steps:
1) weighing 220 parts by weight of reduced iron powder, pouring 20 parts by weight of pure water, and stirring and wetting;
2) adding 50 parts by weight of mixed acid solution containing 0.5 percent of phosphoric acid, 0.03 percent of nitric acid and 0.005 percent of oxalic acid, stirring uniformly, reacting for 4 hours, simultaneously heating to 120 ℃, and stir-frying the iron powder to be dry;
3) adding 30 parts by weight of pure water, fully stirring and wetting, adding 1.3 parts by weight of zirconium oxide powder, stirring until the mixture is uniformly mixed, adding 60 parts by weight of 0.8% sodium silicate aqueous solution, uniformly stirring, adding 30 parts by weight of silane A151, continuously stir-frying until the mixture is dry, adding 15 parts by weight of zinc stearate, and continuously stirring until the mixture is uniformly mixed;
4) mixing the mixture at 8.0T/cm3Pressing into iron powder core;
5) heating the iron powder core to 180 ℃, carrying out annealing heat treatment for 2 hours, cooling to room temperature, then carrying out vibration grinding for 30 minutes, and removing burrs;
6) and spraying epoxy resin paint on the iron powder core, wherein the thickness of a paint film is 0.15mm, and thus obtaining the non-aging iron powder core.
Example 2
A preparation method of an unaged iron powder core comprises the following steps:
1) weighing 280 parts by weight of reduced iron powder, pouring 30 parts by weight of pure water, and stirring and wetting;
2) adding 70 parts by weight of mixed acid solution containing 0.8 percent of phosphoric acid, 0.05 percent of nitric acid and 0.008 percent of oxalic acid, stirring uniformly, reacting for 5 hours, simultaneously heating to 150 ℃, stir-frying the iron powder until the iron powder is dry
3) Adding 50 parts by weight of pure water, fully stirring and wetting, adding 1.5 parts by weight of zirconium oxide powder, stirring until the mixture is uniformly mixed, adding 80 parts by weight of 1.2% sodium silicate aqueous solution, uniformly stirring, adding 50 parts by weight of silane A151, continuously stir-frying until the mixture is dry, adding 20 parts by weight of zinc stearate, and continuously stirring until the mixture is uniformly mixed;
4) pressing the mixture into a dust core at the pressure of 10.0T/cm 3;
5) heating the iron powder core to 200 ℃, annealing for 3 hours, cooling to room temperature, then vibrating and grinding for 45 minutes, and removing burrs;
6) and spraying epoxy resin paint on the iron powder core, wherein the thickness of a paint film is 0.21mm, and thus obtaining the non-aging iron powder core.
Example 3
A preparation method of an unaged iron powder core comprises the following steps:
1) weighing 350 parts by weight of reduced iron powder, pouring 40 parts by weight of pure water, and stirring and wetting;
2) adding 80 parts by weight of mixed acid solution containing 1.2 percent of phosphoric acid, 0.08 percent of nitric acid and 0.012 percent of oxalic acid, uniformly stirring, reacting for 6 hours, simultaneously heating to 180 ℃, and stir-frying the iron powder until the iron powder is dry;
3) adding 60 parts by weight of pure water, stirring until the pure water is fully wetted, adding 2.1 parts by weight of zirconium oxide powder, stirring until the pure water is uniformly mixed, adding 100 parts by weight of 1.5% sodium silicate aqueous solution, stirring uniformly, adding 70 parts by weight of silane A151, continuously stir-frying until the pure water is dry, adding 40 parts by weight of zinc stearate, and continuously stirring until the pure water is uniformly mixed;
4) pressing the mixture into a dust core at the pressure of 12.0T/cm 3;
5) heating the iron powder core to 230 ℃, carrying out annealing heat treatment for 4 hours, cooling to room temperature, then carrying out vibration grinding for 60 minutes, and removing burrs;
6) and spraying epoxy resin paint on the iron powder core, wherein the thickness of a paint film is 0.26mm, and thus obtaining the non-aging iron powder core.
Comparative example 1
An iron powder core was prepared as comparative example 1 by following the procedure described in example 1, using the same weight part of phosphoric acid in step 2) instead of the mixed acid solution, but without changing the others.
Comparative example 2
An iron powder core was prepared as comparative example 2 by following the procedure described in example 1, using an equal amount of silica instead of zirconia in step 3), but otherwise unchanged.
Example 4
The iron powder cores prepared in examples 1 to 3 and comparative examples 1 and 2 were tested according to GB/T19346.1 for 3 times, and the test results are shown in Table 1 by taking the average value.
TABLE 1
According to the test data in table 1, the present application has lower power loss, higher resistivity and magnetic flux density, and can maintain lower inductance quality factor loss under long-term operation at high temperature compared with the comparative example. Therefore, the mixed acid solution pretreatment and the rare earth oxide are beneficial to improving the magnetic property of the iron powder core which runs for a long time at high temperature, ensuring that the obvious aging phenomenon does not occur due to high temperature, obviously reducing the loss of the magnetic core and prolonging the service life of the iron powder core.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. The high-temperature non-aging iron powder core is characterized by being mainly prepared from the following raw materials:
100-500 parts of reduced iron powder, 10-100 parts of mixed acid solution, 1-10 parts of inorganic high-temperature insulating agent, 10-200 parts of inorganic high-temperature binder, 10-100 parts of organosilane coupling agent, 10-50 parts of lubricant and 1-20 parts of epoxy resin paint.
2. The high temperature non-aging powdered iron core according to claim 1, wherein the mixed acid solution is composed of phosphoric acid 0.5-5%, an oxidizing agent 0.01-1%, and an organic acid 0.001-0.05%.
3. The high temperature non-aging powdered iron core according to claim 2, wherein the oxidizing agent is a combination of at least one of nitric acid, chromic acid, hydrogen peroxide, potassium permanganate, sodium hypochlorite, and ozone.
4. The high-temperature non-aging fine iron core according to claim 2, wherein the phosphoric acid is 0.1 to 3.0% of the fine reduced iron, and the organic acid is 0.001 to 0.05% of the fine reduced iron.
5. The high temperature unaged fine iron powder core according to claim 2, wherein the inorganic high temperature insulating agent is a combination of at least one of yttria, zirconia, holmium oxide, cerium oxide, tantalum oxide, titanium oxide, silicon oxide, aluminum oxide, etc., the inorganic high temperature binder is composed of at least one of alumina, silica, boron oxide, magnesium oxide, zirconia, zinc oxide, calcium aluminate, and the lubricant comprises at least one of zinc stearate, graphite powder, mica, talc, barium hydroxide, borax.
6. The method for preparing a high-temperature non-aged fine iron core according to claims 1 to 5, comprising the steps of:
1) weighing reduced iron powder according to the weight part ratio, pouring a certain weight part of water, and stirring and wetting;
2) adding a mixed acid solution into the material obtained after wetting in the step 1), uniformly stirring, heating to react for a period of time, and stir-frying the iron powder to be dry;
3) adding water into the mixture obtained in the step 2), stirring the mixture to be fully wetted, adding an inorganic high-temperature insulating agent, stirring the mixture until the mixture is uniformly mixed, adding an inorganic high-temperature binder, stirring the mixture uniformly, adding an organosilane coupling agent, continuously stir-frying the mixture until the mixture is dry, adding a lubricant, and continuously stirring the mixture until the mixture is uniformly mixed to obtain a mixture;
4) pressing the mixture obtained in the step 3) into a dust core;
5) annealing and heat-treating the iron powder core prepared in the step 4), cooling to room temperature, and then performing vibration grinding to remove burrs;
6) and 5) spraying epoxy resin paint on the iron powder core prepared in the step 5), and airing to obtain the high-temperature non-aging iron powder core.
7. The method for preparing a high temperature non-aged fine iron core according to claim 6, wherein the amount of water used in step 1) is 1/10-1/3 of the fine reduced iron.
8. The method for preparing a high-temperature non-aged fine iron core according to claim 6, wherein the temperature after the temperature rise in the step 2) is 80 to 200 ℃, and the reaction time is 1 to 10 hours.
9. The method as claimed in claim 6, wherein the annealing temperature in step 5) is 100-300 ℃, the annealing time is 1-8 hours, and the vibration milling time is 10-120 minutes.
10. The method for producing a high-temperature non-aged fine iron core according to any one of claims 7 to 9, wherein the thickness of the epoxy resin paint film in step 6) is 0.1 to 0.5 mm.
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| CN202111595687.4A CN114284014A (en) | 2021-12-24 | 2021-12-24 | High-temperature non-aging iron powder core and preparation method thereof |
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| CN202111595687.4A CN114284014A (en) | 2021-12-24 | 2021-12-24 | High-temperature non-aging iron powder core and preparation method thereof |
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